The advantages and general design of intelligent adaptive surfaces are well known, as are various methods for implementation in particular articles, such as seating surfaces, mattresses, and the like. However, miniaturization and ruggedization of these systems remains an issue.
Likewise, cryotherapy systems are also known, which facilitate healing and reduce inflammation. The combination of cryotherapy to about 4.degree. C. and controlled external pressure of about 0.4-0.8 psi has been clearly documented.
In various types of athletic footwear, it is recognized that the comfort and fit of the footwear can affect the athletic performance. In order to increase both the comfort and fit of footwear, manufacturers have incorporated inflatable bladders of various designs into the construction of the footwear. The development, incorporation, and use of inflatable air bladders within athletic footwear was and is particularly appropriate for ski boots used for downhill skiing. Thus, a number of patents relate to the field of ski boots which incorporate inflatable air bladders, for example, German Patent No. 2,162,619, and U.S. Pat. No. 4,662,087. While the original designs for ski boots having air bladders incorporated the use of an external pressurizing device such as a hand pump, more recent designs incorporate the design of the pump into the article of footwear, such as for example the ski boot of U.S. Pat. No. 4,702,022. Various footwear designs also provide an compressor which is actuated by user activity, providing a supply of compressed air while the footwear is in vigorous use.
The demands for comfort and snugness of fit in other athletic events has resulted in the use of the inflatable bladders originally developed for ski boots in various types of athletic footwear, including athletic shoes used for basketball and other sports. There are presently available athletic shoes incorporating an air pump, such as depicted within U.S. Pat. No. 5,074,765, to inflate air bladders located within the sole of the shoe, or alternatively, bladders located in portions of the upper or the tongue of the athletic shoe. The advantages of these types of shoes is manifested primarily by their increased comfort and the secure positioning or fit of the foot within the shoe. Another benefit derived from the use of air bladders is the potential for reduction of forces transmitted through the shoe to the foot and ankle of the wearer during performance of the athletic endeavor. Thus, current athletic shoes having incorporated air bladders provide enhanced comfort and fit, while also reducing the occurrence of various types of injuries.
For typical athletic shoes currently commercially available which incorporate both the inflatable air bladders and a pump inflation means, the comfort and fit of the article of footwear is adjusted by inflating the air bladder by use of the pump after securing the footwear about the foot. The wearer simply inflates the air bladder until a particular pressure level, or fit, is felt by the foot. However, due to the rigors of various athletic events, and because the human foot tends to swell and contract with varying levels of activity, it is very difficult for the individual to obtain a consistent fit from one use to the next, or to recognize the difference in their performance, based upon a pressure setting for the air bladders that is merely sensed by the foot. Therefore, designs have been proposed which include a pressure sensor, for example, see U.S. Pat. No. 5,588,227, expressly incorporated herein by reference.
Heat transfer systems are desirable under many circumstances. Heating is generally easily accomplished, by dissipating power. Cooling, however, generally requires coupling an endothermic reaction with an exothermic reaction of equal or greater magnitude, although in a different environment. Thus, heat may be transferred without violating the laws of thermodynamics. Many different types of cooling systems are known. However, efficient active miniature (&lt;300 W thermal transfer capacity) cooling systems pose many design compromises, and few optimal designs are available.
Cooling is generally provided in a number of ways. First, heat in an object to be cooled may be lost by transferring heat energy from a hotter mass to a cooler mass, which may be an active, facilitated or conduction process. Second, an artificial gradient may be created to allow heat to be moved effectively from a hotter to a colder mass. This process includes, e.g., compressing a gas to increase its temperature, then shedding the heat resulting from the compression to the environment, followed by decompressing the cooled gas in a different location to a net colder state than prior to compression. Various phase change, e.g., vaporization, solidification, adsorption, dissolution, etc., and irreversible processes may also be used to provide cooling. Thermoelectric junctions may also be used to cool, although their power efficiency is low.
"Cryotherapy" is defined as the treatment of injury using the benefits derived by application of cold, optionally with external applied pressure. Such therapy has been shown to be particularly effective in treating musculoskeletal trauma resulting from an injury or by the application of a wrenching force to the body, e.g., lacerations, sprains, strains, fractures, contusions or fractures. This type of injury may be accompanied by a tearing of tendons, ligaments or other tissue, and triggers the body's own natural healing process. See Sloan et al., "Effects of Cold and Compression on Edema", The Physician and Sports Medicine, 16(8) (1988); Bailey, "Cryotherapy", Emergency, 40-43 (August, 1984); Cryomed Brochures.
In order to minimize secondary trauma subsequent to a primary musculoskeletal insult, prompt treatment is required. Secondary trauma results from the body's own healing process which acts by first degrading injured tissue and then rebuilding, typically with scar tissue. This treatment should immobilize the trauma site, ease pain and minimize the risk of secondary tissue damage which usually accompanies breaks, sprains and strains.
An injury will almost immediately produce pain and will be followed rapidly by an accumulation of blood, interstitial fluids and lymphatic fluids. In addition, injured cells will release histamine, cytokines and other substances which act to perpetuate the inflammation process and increase the permeability of the vasculature. For a number of reasons, a free radical process ensues. The inflammatory process also causes the release of chemicals and causes conditions under which damaged collagen dissolves or degrades. The extent of this collagen damage depends on a number of factors, including the extent of the inflammatory process.
The collagen removal process forms a part of the normal healing process, and under certain circumstances, is desirable in that it allows reconstruction of the tissue by collagen regrowth. Unfortunately, in most circumstances, the damaged collagen is replaced by a random regrowth, forming a scar. While scar formation may be necessary to replace the lost tissue matrix, in many circumstances the scar impairs a return to normal functioning. Thus, scar formation in a joint, where uninjured collagen is linearly dispersed, tends to proceed after the injury by randomly-fashioned replacement, which may interfere with joint mobility and produce chronic pain.
The body's healing response is natural and necessary for restoring the functioning of the damaged tissue and the body as a whole. This natural process may produce detrimental side effects that, if not properly controlled, can exacerbate patient discomfort, impede recovery and result in long term or permanent impairment of the injured area.
Damage to the tissue may allow the formed blood components to leave the vasculature in the area of the injury (called a "hematoma"). Enhanced permeability of the blood vessels may lead to an accumulation of fluids in the extracellular space (called "edema"). This excess or accumulated fluid causes swelling, which may form part of a self-perpetuating process of inflammation. Further, in circumstances when the pressure in the tissue exceeds the perfusion pressure in the capillary microcirculation, the flow of oxygenated blood in that tissue becomes insufficient and the tissue becomes hypoxic, eventually leading to hypoxic necrosis. Thus, leakage of fluids at or near arterial blood pressures will impede circulation in the tissue. This process, called a "compartment syndrome", may occur when an external pressure is applied to tissues which exceeds the perfusion pressure, or when an inflammatory process in a tissue compartment causes the buildup of interstitial fluid with an increase in pressure in the compartment.
Secondary trauma is a process by which a primary injury causes inflammation, edema and/or hematoma, which secondarily is responsible for further tissue damage. If the secondary process is treated, slowed or its course modified, the extent of this secondary injury may be reduced. Thus, after a musculoskeletal injury, edema and/or hematoma may result, causing tissue compression and other effects. This compression can result in further injury while the swelling lasts, and prevent other treatments from being effectively applied. Under normal circumstances, secondary trauma lasts approximately one to three days after a primary musculoskeletal insult, and during this period, further definitive treatment, including surgery, may have to be postponed.
While the natural healing process is often sufficient and yields acceptable results, the fields of medicine and surgery have developed to overcome its shortcomings. Thus, there are a number of circumstances where it is desirable to circumvent or preempt the body's natural healing process and provide an external treatment.
It is known that the immediate application of compression and cold will slow down tissue metabolism and response to injury so that a slower and more controlled process may ensue. With the application of cold and pressure, this secondary trauma response may be blunted. Thus, the art teaches the use of ice pack compresses or other cooling devices, which may involve ice or ice-cooled water, endothermic reactions (blue ice), primary cooling with a volatile refrigerant (Roslonski, Cryomed), or secondary cooling with a refrigeration system and circulating antifreeze solution (Seabrook).
Besides injuries, there are other applications for cryotherapy. For example, normal tissues, such as hair follicles, may be spared the effects of cancer chemotherapy by the topical application of pressure and cold around the time of chemotherapeutic treatments. See, e.g., Dean, J. O. et al., `Prevention of Doxorubicin-Induced Scalp Hair Loss," New England Journal of Medicine, Dec. 27, 1979, 301(26):1427-29; H. F. P. Hillen, et al., "Scalp Cooling By Cold Air for the Prevention of Chemotherapy-Induced Alopecia," Netherlands Journal of Medicine, 37 (1990) 231-235; Cline, B. W., "Prevention of Chemotherapy-Induced Alopecia: a Review of the Literature,` Cancer Nursing, 1984, 7:221-228: Dean, J. O., et al. "Scalp Hypothermia: A Comparison of Ice Packs and the Kold Kap in the Prevention of Doxorubicin-Induced Alopecia," J. Clin. Oncol., 1983, 1:33-37; Bulow J., et al., "Frontal Subcutaneous Blood Flow, and Epi- and Subcutaneous Temperatures During Scalp Cooling in Normal Man," Scand. J. Clin. Lab Invest., 1985, 45:505-508; Parbhoo, S. P., et al., "An Improved Technique of Scalp Hypothermia to Prevent Adriamycin/Mitozantrone Induced Alopecia in Patients with Advanced Breast Cancer," Clinical Oncology and Cancer Nursing, Stockholm, 1986, 232 (Abstract); Gregory, R. P., et al., "Prevention of Doxorubicin-Induced Alopecia by Scalp Hypothermia: Relation to Degree of Cooling," Br. Med. J., 1982, 284:1674. Chemotherapeutic agents which cause alopecia which may be reduced by cryotherapy include anthracycline antibiotics, e.g. doxorubicin or epirubicin, nucleoside analogs, e.g. 6-fluorouracil, folate antagonists, e.g. methotrexate and alkylating agents, e.g. cyclophosphamide.
In addition, cryotherapy may also be employed for other medical purposes, where control of metabolic rate is desired.
For example, U.S. Pat. No. 3,871,381 to Roslonski teaches a cryotherapy device which applies both cold and pressure to an extremity which involves the introduction of a pressurized volatile refrigerant liquid, e.g., Freon.RTM. (a chlorofluorocarbon or "CFC"), through a controlled flow rate valve, which cools a maze passage in a flexible device. A pressure relief valve maintains a back-pressure in the system. It is also known to circulate a cooled fluid through a conduit in a bandage. Cold and pressure are therefore known treatments for traumatic injuries, as well as inflammatory pathologic processes which involve externally accessible organs.
The device disclosed in Roslonski, U.S. Pat. No. 3,871,381, however, presents a number of drawbacks. First, the design of Roslonski's flow path allows refrigerant liquid to pool in some areas, while other areas do not receive sufficient liquid refrigerant, thus causing uneven tissue cooling. Further, a crimp in one portion of the device may block a flow of coolant liquid to other portions of the device, likewise causing uneven cooling and additionally causing noise due to turbulent flow and focal refrigerant vaporization. The temperature of these known CFC-based systems depend in large part on the composition of the refrigerant fluid employed, which usually have an effective boiling plateau slightly above the freezing point of water (0.degree. C.). These systems therefore provide a relatively uncontrolled temperature, seeking to maintain a desired temperature by providing an excess of refrigerant having a boiling point of about the desired final temperature. In these systems, the only way to control the temperature, other than starving the cooling device (to achieve a non-equilibrium condition), is to vary the allow refrigerant composition. The known systems do not provide a uniform response to refrigerant starving, producing temperature non-uniformities and unpredictability. These known systems also have an operating temperature which depends in lesser part on the rate at which heat is removed by the refrigerant, which in turn depends on the rate of volatilization of the refrigerant. For example, a greater volume of refrigerant will withdraw more heat than a lesser volume, thus producing a lower temperature. Other performance factors include the ambient temperature, ambient humidity, body temperature, atmospheric pressure, pressure within the device, refrigerant composition and flow rate of the refrigerant. The rate of volatilization of a refrigerant also relates to flow turbulence and nucleation centers.
Chlorofluorocarbon refrigerants are known to be available and to be used alone or in mixtures. Some mixtures have boiling characteristics with a plurality of plateaus. Known refrigerants (Freon.RTM.) such as R-11, R-12 and R-114 have boiling points of approximately 24.degree. C. (75.degree. F.), -30.degree. C. (-22.degree. F.) and 3.8.degree. C. (39.degree. F.) respectively, and these may be mixed to form a refrigerant composition having boiling plateaus at approximately the boiling points of the individual components. See Freon Product information, Du Pont (1973). In a Roslonski-type system, the lowest boiling component of such a refrigerant mixture acts to propel the refrigerant from the canister and precool the remaining refrigerant liquid as it enters the cooling matrix. The mid temperature boiling refrigerant acts to cool the tissue by boiling in the cooling matrix at a temperature approximately the same as the desired tissue temperature. Lastly, the highest boiling component acts as a heat transfer agent to improve the effectiveness of the device, by stabilizing the operation over a range of environmental conditions and helping to distribute the vaporizing refrigerant. The highest boiling component generally vaporizes before it reaches the end of the cooling matrix. Thus, the lowest temperature in the heat transfer portion of the cryotherapy device, using the known CFC refrigerants, will be around 0-4.degree. C., thereby posing only a small risk of tissue freezing (frostbite), unless too much refrigerant mixture is injected from the canister to the cooling matrix so that the lowest boiling component is present in substantial quantities, or if the tissue is poorly vascularized. These mixtures, therefore, may be used in open-loop cryotherapy systems, with minimal or imprecise flow regulation. In practice, these devices pose low risk of tissue freezing and are effective. However, these systems are environmentally unfriendly, venting chlorofluorocarbons into the atmosphere. These CFC's are known ozone depleting chemicals and greenhouse gasses. Known refrigerant compositions which are more acceptable do not completely emulate CFCs, and typically are themselves greenhouse gasses and therefore should not be indiscriminately released into the environment.
CFC substitutes, which are generally fluorinated hydrocarbon molecules (HFC's), fluorocarbons (FC's), hydrochlorofluorocarbonis (HCFC's) or hydrocarbons, are or are becoming available. Because each composition is distinct, there is no correspondence or equivalency between the prior employed CFC gasses and these other gasses, each gas having its own unique properties and compatibilities with mechanical components. Therefore, prior teachings as to how to provide a portable refrigeration arrangement using specific CFC's do not provide specific teachings as to how to design a system employing non-CFC refrigerants.
Certain available known second generation (HCFC) mid-boiling refrigerants, including R-124 and R-142B, have much lower boiling points than the corresponding mid-boiling CFC components, e.g. -11.degree. C. and -9.degree. C. respectively and therefore pose a substantial risk of tissue freezing when substantial quantities of refrigerant liquid (at about atmospheric pressure) vaporize in proximity to an aqueous liquid or biological tissue to be cooled, in contrast to Freon R-114 (BP around 3.8.degree. C.) which poses low risk of frostbite. The major penalty excess flow rate in an R-114 based system is the premature exhaustion of the CFC supply and a high flow rate of gas (and/or liquid in extreme cases) exhausted from the system.
A particular difficulty results from a difference in boiling points of the normally available non-CFC refrigerants as compared to the traditionally used CFC counterparts. Lower boiling point substitutes create a risk of spot freezing or frostbite, even if the heat of vaporization of the amount of fluid supplied is insufficient to freeze the bulk of the tissue or fluid to be cooled. The prior art teaches against the use of such low boiling refrigerants at atmospheric pressure in close potential proximity to skin or aqueous liquids, which are not desired to be frozen. If the boiling point is too high, it will be difficult to reach a desired final temperature.
Many systems have been proposed for cooling beverages outside of traditional refrigeration systems, which may be large or clumsy. These past proposals have employed thermoelectric cooling modules (TEMs, employing Peltier junctions), compressed gasses, CFC refrigerants, and endothermic reactions (absorption refrigeration, typically with one solid phase component, such as a zeolite).
A range of refrigerant compositions (both pure refrigerant and combinations of refrigerants) considered useful for cooling of aqueous fluids below atmospheric temperatures are known, typically having a boiling point of about -65 to +40.degree. C. at approximately atmospheric pressure, and a heat of vaporization of in excess of about 10 cal/gm. These compositions are permitted to vaporize in an expansion chamber (evaporator), resulting in a cooling effect.
While refrigeration systems may operate in a single phase, i.e., expansion of a compressed gas, high efficiency at environmental temperatures may often be advantageously obtained when a fluid boils or evaporates, carrying the heat of vaporization with the gas phase from the site of cooling. Thus, the area in proximity to the phase change will be cooled, and the gas is expelled to the atmosphere or to a recycling (reliquification) system. This phase change generally allows substantial heat energy transfer with comparatively lower temperature gradients than single phase systems, i.e., gas expansion systems. These smaller temperature gradients allow temperature buffering around a desired temperature range, thus allowing a degree of self regulation. The fluid also typically withdraws more heat per mass and volume unit than a gas. Thus, a system employing a liquid phase may also allow a more compact system, due to the higher heat energy capacity of liquids than gasses. Temperature buffering at a temperature around 0.degree. C. is preferred because it limits freezing of an object to be cooled and minimizes the danger of frostbite and freezing of biological tissues.
Hadtke, U.S. Pat. No. 5,449,379, expressly incorporated herein by reference, relates to an improvement on the system of Roslonski. This system uses Dymel.RTM. or Freon refrigerants, and is fabricated of polyvinyl chloride or polypropylene coated woven nylon. An aluminized Mylar.RTM. thermal transfer patch, not in contact with the refrigerant, may be employed to direct heat transfer to an area of interest.
The following patents relate to known refrigerant systems: Lodes, U.S. Pat. No. 2,529,092; Senning, U.S. Pat. No. 2,641,579; Ashkenaz, U.S. Pat. No. 2,987,438; Munro, U.S. 3,733,273; Borchardt, U.S. Pat. No. 3,812,040; Hutchinson, U.S. Pat. No. 3,940,342; Murphy, U.S. Pat. No. 4,055,054; Orfeo, U.S. Pat. No. 4,533,536; Nikolsky, U.S. Pat. No. 4,495,776; Ermack, U.S. Pat. No. 4,510,064; and Nikolsky U.S. Pat. No. 4,603,002.
Brown, U.S. Pat. No. 2,696,395 relates to a pneumatic pressure garment for application of therapeutic pressure.
Gottfried, U.S. Pat. No. 3,153,413 relates to a pressurized bandage with splint functions.
Towle, et al., U.S. Pat. No. 3,171,410 relates to a pneumatic wound dressing.
Gardner, U.S. Pat. No. 3,186,404 relates to a pressure device for therapeutic treatment of body extremities.
Romano, U.S. Pat. No. 4,135,503 relates to an orthopedic device having a pressurized bladder for spinal treatment.
Curlee, U.S. Pat. No. 4,622,957 relates to a therapeutic corset for applying pressure to a portion of the back.
Cronin, U.S. Pat. No. 4,706,658 relates to a gloved splint, providing a shock absorbing treatment and possible heat removal from the hand.
Johnson, Jr. et al., U.S. Pat. No. 5,230,335, and Johnson Jr. et al., U.S. Pat. No. 5,314,455, both relate to a leg treatment system having a cold thermal fluid and having means for applying pressure.
Smith, U.S. Pat. No. 5,324,318, relates to a cryotherapy apparatus having a cold compress and a gravity fed cold liquid. Smith, U.S. Pat. No. 5,170,783, relates to a cryotherapy procedure employing a gravity pressurized cold liquid.
French et al., U.S. Pat. No. 4,844,072, relates to a heated or cooled liquid thermal therapy system.
Wright, U.S. Pat. No. 5,172,689, relates to a cryotherapy sleeve for therapeutic compression.
Meserlian, U.S. Pat. No. 5,167,227, relates to an apparatus for massaging or supporting the legs of a horse.
Gammons et al., U.S. Pat. No. 4,149,541, relates to a flexible circulating pad which ensures fluid flow to all areas.
Sauder, U.S. Pat. No. 4,170,998, and Sauder, U.S. Pat. No. 4,184,537, both relate to a limb refrigeration device for cryotherapy.
Kolstedt, U.S. Pat. No. 4,335,716, relates to a device for circulating pressurized cold fluid in a sleeve for cryotherapy.
Arkans, U.S. Pat. No. 4,338,944, relates to a cooled liquid cryotherapy device.
Larsen, U.S. Pat. No. 4,998,41 5, relates to a body cooling apparatus including a compressor and a condenser.
Tucker, et al., U.S. Pat. No. 4,442,834, relates to a pneumatic splint device.
Robbins et a., U.S. Pat. No. 4,175,297 relates to an inflatable pillow support having automated cycling inflation and deflation of various portions thereof.
Artemenko et al., U.S. Pat. No. 3,683,902 relates to a medical splint apparatus, having an inflatable splint body and a circulated cooling agent, cooled by solid carbonic acid CO.sub.2.
Davis et al., U.S. Pat. No. 3,548,819 relates to a pressurized splint adapted to apply a thermal treatment to a human extremity.
Nicholson, U.S. Pat. No. 3,561,435 relates to on inflatable splint having a coolant chamber to apply pressure and cool to a human extremity.
Berndt et al., U.S. Pat. No. 3,623,537 relates to a self-retaining cold wrap which treats an injury with cold and pressure.
Baron, U.S. Pat. No. 4,300,542 and Baron, U.S. Pat. No. 4,393,867 both relate to a self-inflating compression device for use as a splint.
Golden, U.S. Pat. No. 4,108,146 relates to a cooling thermal pack with circulating fluid which conforms to body surfaces to apply a cooling treatment.
Moore et al., U.S. Pat. No. 4,114,620 and Gammons et al., U.S. Pat. No. 4,149,541 relate to treatment pads with circulating fluid for providing a hot or cold treatment to a patient.
Brannigan et al., U.S. Pat. No. 4,575,097 relates to a thermally capacitive compress for applying hot or cold treatments to the body.
Arkans., U.S. Pat. No. 4,331,133 relates to a pressure measurement apparatus for measuring the pressure applied by a pressure cuff to a human extremity.
Kiser et al., U.S. Pat. No. 4,502,470 relates to a device for assisting in pumping tissue fluids from a foot and ankle up the leg.
Stark, U.S. Pat. No. 3,000,190 relates to an apparatus providing body refrigeration, for use in high ambient temperature environments by workers.
FR 2,133.680 relates to a system for cooling objects, including beverage cans, using fluorocarbons, e.g. Freon.
Nelson, U.S. Pat. No. 2,051,100, Burkhardt, U.S. Pat. No. 2,463,516 and Richards, U.S. Pat. No. 4,103,704 relate to pressure relief valves. Ninomiya et al., U.S. Pat. No. 4,286,622 relates to a check valve assembly.
Martin et al., U.S. Pat. No. 2,550,840, Both et al., U.S. Pat. No. 2,757,964, Galeazzi et al., U.S. Pat. No. 2,835,534, Mura, U.S. Pat. No. 3,314,587, White, U.S. Pat. No. 3,976,110 and Turner, U.S. Pat. No. 4,281,775 relate to pressurized container dispensing valves and systems containing same. Frost, U.S. Pat. No. 3,273,610 relates to a pressurized container valve and detachable dispensing attachment device.
Nakano, et al., U.S. Pat. No. 4,958,501, relates to a refrigerant charging apparatus for charging a refrigerant, including a refrigerant can, an upper can-opening part, a conduit having two inner passages for indication and charging, respectively, a lower can-opening part, and a level indicator communicating with the refrigerant can via both can-opening parts, for indicating a remaining quantity of the refrigerant in the can.
Chruniak, U.S. Pat. No. 5,181,555, relates to a climate controlled food and beverage container which operates off an automotive climate control system. Howell, U.S. Pat. No. 5,203,833, also relates to a food storage container operating off an automotive air conditioning system. Fujiwara, et al., U.S. Pat. No. 4,637,222, relates to an automobile refrigerator detachably connected to the air conditioner of a vehicle. Maier, et al., U.S. Pat. No. 5,007,248, relates to an automobile air conditioner driven beverage cooling system.
Kitayama, U.S. Pat. No. 5,189,890, relates to a portable chiller for chilling an ophthalmic solution, cosmetic preparation, beverage or the like. This portable chiller consists generally of a cylinder filled with a liquefied refrigerant gas and a chiller case.
Ramos, U.S. Pat. No. 5,201,183, relates to a cooling device for beverage cans which cools by releasing liquid nitrogen or liquid air from a containment "bubble".
Sundlhar, et al., U.S. Pat. No. 5,201,193, relates to a cooling device for beverages which cool by releasing liquid carbon dioxide. Saia, et al., U.S. Pat. No. 5,337,579, also relates to a liquid carbon dioxide cooling system. Fischler, et al., U.S. Pat. No. 4,669,273, relates to a coiled tube insert releasing a liquid refrigerant for cooling a beverage.
Aitchison, et al., U.S. Pat. No. 5,214,933, relates to a liquid pressurized refrigerant system for cooling a fluid container. Beck, U.S. Pat. No. 3,919,856, relates to a liquid refrigerant beverage cooling device. Willis, U.S. Pat. No. 3,987,643, relates to a beverage cooling system employing compressed gas or liquid refrigerant with an improved heat exchanger system. Barnett, U.S. Pat. No. 4,584,484, relates to a liquid refrigerant system for cooling a can. Johnson, U.S. Pat. No. 4,640,101, relates to a liquid refrigerant beverage chilling mechanism. Tenebaum, et al., U.S. Pat. No. 4,640,102, also relates to a liquid refrigerant beverage cooling mechanism.
Dodd, U.S. Pat. No. 4,319,464, relates to a container which is cooled by the release of a pressurized refrigerant. Kim, U.S. Pat. No. 4,628,703, and Kim, et al., U.S. Pat. No. 4,679,407, both relate to a refrigerant cooled can mechanism. Shen, U.S. Pat. No. 4,656,838, relates to a pressurized coolant for a beverage can. Chou, U.S. Pat. No. 4,925,470, relates to a self cooling can having a pressurized refrigerant.
Ladany, U.S. Pat. No. 3,862,548, relates to a beverage cooling device which employs compressed gas. Nof, U.S. Pat. No. 4,597,271, relates to a pressurized gas method for cooling a container and liquid contained therein. Riley, U.S. Pat. No. 3,881,321, also relates to a beverage cooling device which preferably carbonates the beverage on release of the gas.
Rhyne Jr., et al., U.S. Pat. No. 4,054,037, relates to a beverage cooler for sequentially cooling a plurality of beverage containers.
Holcomb, U.S. Pat. No. 4,668,395, relates to a food container cooling system having a pressurized refrigerant fluid which is released into an expansion chamber. Campbell, U.S. Pat. No. 4,434,158, relates to an insulin cooling device including a refrigerating agent. Ehmann, U.S. Pat. No. 4,429,793, also relates to an insulating container with a refrigerant.
Manz, et al., U.S. Pat. No. 5,497,625, relates to a Thermoelectric refrigerant handling system.
Merritt-Munson, et al., U.S. Pat. No. 5,237,838, relates to a refrigerant cooled cosmetic bag. Martello, et al., U.S. Pat. No. 4,584,847, relates to a liquid refrigerant system for cosmetics.
Merritt, et al., U.S. Pat. No. 5,353,600, relates to a solar powered thermoelectric cooler for a cosmetic bag which seeks to employ heat produced by the thermoelectric cooling element to recharge a rechargeable power source.
Collard, U.S. Pat. No. 5,247,798, relates to a thermoelectric refrigeration device. Rudick, U.S. Pat. No. 4,671,070, relates to a thermoelectric beverage can cooler.
Harris, et al., U.S. Pat. No. 4,280,330, relates to a thermoelectric vehicle cooling system.
Kitayama, U.S. Pat. No. 5,287,707, relates to a portable vaporizing liquid refrigerant chiller device.
Isaacson, et al., U.S. Pat. No. 5,313,809, relates to an insulating wrap having a eutectic solution in a film barrier container.
Baroso-Lujan, et al., U.S. Pat. No. 5,325,680, relates to a Freon-22 cooled beverage container which flashes liquid Freon into an evacuated space.
Goble, U.S. Pat. No. 5,214,929, relates to a non-CFC substitute refrigerant for R-12, including 2-20% isobutane (R-600a), 41-71% chlorodifluoromethane (R-22) and 21-51% chlorodifluoroethane (R-142b).
Murphy, U.S. Pat. No. 3,901,817, relates to a low boiling azeotropic or essentially azeotropic mixtures containing monochlorotrifluoromethane and methyl fluoride.
Murphy, et al., U.S. Pat. No. 4,054,036, relates to constant boiling mixtures of 1,1,2 trichorotrifluoroethane and cis-1,1,2,2-tetrafluorocyclobutane.
Murphy, et al., U.S. Pat. No. 4,055,049, relates to constant boiling mixtures of 1,2 difluoroethane and 1,1,2-tricloro-1,2,2-trifluoroethane.
Murphy, et al., U.S. Pat. No. 4,055,054, relates to constant boiling mixtures of dichloromonofluoromethane and 1-chloro-2,2,2-trifluoroethane.
Murphy, et al., U.S. Pat. No. 4,057,973, relates to constant boiling mixtures of 1-chloro-2,2,2-trifluoroethane and 2-chloroheptafluoropropane.
Murphy, et al., U.S. Pat. No. 4,057,974, relates to constant boiling mixtures of 1-chloro-2,2,2-trifluoroethane and octafluorocyclobutane.
Murphy, et al., U.S. Pat. No. 4,101,436, relates to constant boiling mixtures of 1-chloro-2,2,2-trifluoroethane and hydrocarbons.
Ostrozynski, et al., U.S. Pat. No. 4,155,865, relates to constant boiling mixtures of 1,1,2,2-tetrafluoroethane and 1,1,1,2-tetrafluorochloroethane.
Ostrozynski, et al., U.S. Pat. No. 4,157,976, relates to constant boiling mixtures of 1,1,1,2-tetrafluorochloroethane and chlorofluoromethane.
Zuber, U.S. Pat. No. 4,169,807 describes an azeotropic composition containing water, isopropanol, and either perfluoro-2-butyltetrahydrofuran or perfluoro-1,4-dimethylcyclohexane. The inventor states that the composition is useful as a vapor phase drying agent.
Van der Puy, U.S. Pat. No. 5,091,104, describes an "azeotropic-like" composition containing t-butyl-2,2,2-trifluoroethyl ether and perfluoromethylcyclohexane. The inventor states that the composition is useful for cleaning and degreasing applications.
Fozzard, U.S. Pat. No. 4,092,257 describes an azeotrope containing perfluoro-n-heptane and toluene.
Batt et al., U.S. Pat. No. 4,971,716 describes an "azeotrope-like" composition containing perfluorocyclobutane and ethylene oxide. The inventor states that the composition is useful as a sterilizing gas.
Shottle et al., U.S. Pat. No. 5,129,997 describes an azeotrope containing perfluorocyclobutane and chlorotetrafluorethane.
Merchant, U.S. Pat. No. 4,994,202 describes an azeotrope containing perfluoro-1,2-dimethylcyclobutane and either 1,1-dichloro-1-fluoroethane or dichlorotrifluoroethane. The inventor states that the azeotrope is useful in solvent cleaning applications and as blowing agents. The inventor also notes that "as is recognized in the art, it is not possible to predict the formation of azeotropes. This fact obviously complicates the search for new azeotrope compositions" (col. 3, lines 9-13).
Azeotropes including perfluorohexane and hexane, perfluoropentane and pentane, and perfluoroheptane and heptane are also known.
Flynn et al., U.S. Pat. No. 5,494,601, provides an azeotropic composition, including a non-cyclic perfluorinated alkane and a hydrochlorofluorocarbon (HCFC) solvent, for example, perfluoropentane and perfluorohexane, and 1,1,1-trifluoro-2,2-dichloroethaiie and 1,1-dichloro-1-fluoroethane.
A hydrofluorocarbon composition, R-236fa, having a boiling point of -1.degree. C. is known. Another known composition is c-(CF.sub.2).sub.4 O, also having a boiling point of about -1.degree. C.
Known aerosol-type cans have a stem which protrudes upwardly, and which is depressed to release the contents of the can. The nozzle is generally secured to the stem by friction. A cap is generally provided to prevent inadvertent release of the contents of the can.
Known volatile refrigerant-supply cans are generally sealed with and release their contents only after a metal diaphragm is punctured. Thus, Vos, U.S. Pat. No. 3,756,472 relates to a system for use with a pressurized canister to produce a desired stream characteristic during ejection of the pressurized contents. This system may be mounted atop an aerosol container.